Conventional ambulatory wheelchairs are not designed to fit into the normal ambulatory passage spaces in homes, shops, and business. Their turning radius can be minimized, but their over-all dimensions often create interference with nearby obstacles.
Prior art wheelchairs have remained essentially the same for many years and are primarily for persons of limited capabilities such as the elderly physically challenged persons. Young and athletic physically challenged persons have to mentally adjust to the sedentary restrictions imposed by current wheel chairs. Their physical ability allow them to actively utilize a carriage without such conventional restrictions and limitations. Instead of putting them in a box, this chair essentially replaces the legs and allows normal torso use above the hips.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention. However, the following U.S. Patents were considered related:
______________________________________ U.S. PAT. NO. ISSUE DATE INVENTOR ______________________________________ 4,927,167 2 May 1990 Davis 4,560,181 24 Dec. 1985 Herron 4,506,901 26 Mar. 1985 Tosti 4,310,167 12 Jan. 1982 McLaurin ______________________________________
The Davis patent discloses an ambulatory wheel stand that includes a user support structure pivotally attached to a wheeled frame. The frame includes a pair of large diameter drive wheels and a pair of front castor wheels. A pivot arm connects the support structure to the frame so that the structure can pivot from an upright to a prone position. As the support structure is lowered to a prone position, a hinge pin slides rearwardly in an elongated slot to prevent the center of gravity from shifting too far forward. Conversely, when in the upright position, the hinge pin slides to the forward end of the slot to maintain the center of gravity in the same position.
The Herron patent discloses a wheel chair and a drive mechanism that is powered by reciprocating operation of a drive lever. The drive mechanism provides a continuously variable gear ratio to allow wheel chair operation at various speeds on different surfaces. The mechanism also allows energy to be transferred during both a forward and rearward stroke of the lever arm.
The Tosti patent discloses a hand-propelled vehicle for particular use of physically challenged individuals. The vehicle includes a frame with a seat portion and an extended front foot platform. Rear wheels support the seat portion relatively to the ground, and the height of the front foot platform is about half the height of the seat portion. This configuration gives the vehicle a low profile to facilitate mounting and dismounting by the user. A hand crank operates chain and sprocket drives and connected to each rear wheel are castors. The castors are mounted to support the front foot platform and to permit the vehicle to turn.
The McLaurin patent discloses a center of gravity wheel chair having an articulated chassis whereby the seat and the center of gravity may be moved forwardly relative to the rear wheels. Thus, increasing the stability and facilitating curb climbing.
The wheel chair has castor wheels in front or back attached in a diamond pattern with the main wheels attached so that lateral side drift is minimized when traversing a sloping surface.
The wheelchair has castor wheels in front or back attached in a diamond pattern with the main wheels attached so thet lateral side drift is minimized when traversing a sloping surface.